I won't comment on Norton on the PC, but running an AV on your phone is not THAT critical if you don't install apps from unknown sources (anything besides Google Play Store is considered 'Unknown Source). Personally, I don't use any security suite on my phone(s). I tried it twice (Kaspersky and Avast) and all it did was slow everything down (and no, both AV were not installed side-by-side. I even did a system wipe on the phone between testing the two).

The best products in our tests (with detection rates of 90% and above) come from the following top 10 companies, listed in alphabetic order: Avast, Dr. Web, F-Secure, Ikarus, Kaspersky, Lookout, McAfee, MYAndroid Protection/MYMobile Security, NQ Mobile/NetQin and Zoner. Users of products made by these companies can be assured that they are protected against malware.

Products with a detection rate of between 65% and 90% can also be considered to be very good and have the potential to join the group of best products above if small changes are made to the set of malware tested. Some of these products only fail to detect just one or two malware families that may not even be prevalent in certain environments. The following 13 products, listed in alphabetic order, fall into this category: AegisLab, AVG Mobilation, Bitdefender, BullGuard, Comodo, ESET, Norton/Symantec, QuickHeal, Super Security, Total Defense, Trend Micro, Vipre/GFI and Webroot
It should be noted that Bitdefender, ESET, Trend Micro and Vipre missed the top category by just a few samples. The average family detection rate for these four products was in the area of 88.1% to 89.9%.

BluePoint, G Data and Kinetoo fall into the third category, namely that of products with a detection rate of between 40% and 65%. It is possible that the manufacturers of these products do not yet have a sufficient infrastructure that enables them to collect a wide range of malware or that they focus on a local market. These products provide reliable malware protection against a few families, but have trouble dealing with and detecting others. It can be expected that these products will improve when their manufacturers focus on a wider variety of malware samples.

The fourth category, which is used for products with a detection rate of less than 40%, does not contain any products from well-known anti-virus protection manufacturers. Some of the products in this category also performed below average in our last test. We have now reviewed two other products that are listed in this final category and we could not clearly determine whether or not they correctly scanned the set of malware test or whether they were actually able to detect anything at all. We were therefore unable to record a detection rate when using our set of well-known samples or the EICAR test file.